New Instrumentation Concepts – Ground-based Optical Telescopes


Keith Taylor,

Departamento de Astronomia, IAG/USP, Brazil


Over the last decade Brazil has gained entry into some of the world's largest telescopes programs.  Instrumenting these telescopes is not only critical to the advancement of the science of observational astronomy but also to the development of new, even larger, facilities to which Brazil may aspire in the future.  The lecture course is designed to  bring students into line with the most recent developments in  the instrumentation of large, ground-based telescopes so that they will be better positioned to take advantage of the growing opportunities in this field.  The mastering of the science of astronomy while at the same time understanding the technology on which it rests is a key to advancement in this highly competitive endevour.

We will begin by discussing basic principles involved in the spectroscopy and interferometry of faint light sources typified by astronomical observations of distant objects; how telescopes are efficiently coupled to instruments in ways which optimize the collection of information and how this information is combined in various ways to address questions of astrophysical significance.  These fundamental principles will include discussions of information theory as applied to both seeing-limited and diffraction-limited observations and signal-to-noise estimates.

We will then explore the basic technologies and techniques which are current today, including advances in optical systems (both spectroscopic and interferometric) and technologies associated with the detection of light.  This will include discussions of various types of diffraction gratings, interferometric techniques based on Fabry-Perots and Michelson Interferometers and, so called, hybrid techniques which are motivated by the trade between recording spectral and spatial information.

We will final touch on the development of instrumentation for adaptive optics techniques as applied to medium to large aperture telescopes looking forward, finally, to the emerging era of instrumentation for 30 to 40m class telescope where adaptive optics moves from be an option to an imperative.




The fabrication and multiple uses of sensors and biosensors


Osvaldo N. Oliveira Jr.,

Instituto de Física de São Carlos, USP, Brazil


Sensing has become ubiquitous in modern life, largely used in security screening, monitoring, diagnostics and in control systems that are pervasive in sophisticated equipment. Many are the materials used for sensing and equally large is the list of principles of detection. 

In this short course I shall discuss the most used sensors for specific sectors, including the automobile industry and security of buildings. Such sensors are usually fabricated with inorganic materials, taking advantage of the well-developed technology of the semiconductor industry that allows for mass production with reduced costs. I shall also elaborate upon sensors produced with organic materials, which may be advantageous owing to the wide variety of properties that can be exploited and controlled for tailored applications. 

Of particular relevance are the sensors and biosensors made with nanostructured films where the control of molecular architecture is possible with layer-by-layer deposition. After presenting the basic concepts for film fabrication and the electrical and optical techniques used for detection, a number of examples will be provided to illustrate the capabilities of organic materials. The first example will be the so-called electronic tongues, which are sensor arrays based on impedance spectroscopy capable of distinguishing complex liquids, such as wines and coffee samples, and detecting trace amounts of impurities in waters. Using machine learning methods, it is also possible to correlate the impedance measurements with the grades assigned by professional tasters, as in an experiment with coffee samples. 

The concept of global selectivity inherent in the electronic tongues can be extended by using sensing units incorporating biomolecules with molecular recognition ability. This is the case of biosensors produced with immobilized antigens used to detect antibodies of specific diseases. Examples will be given of highly-sensitive biosensors used to detect tropical diseases. Because the film-forming methods allow incorporation of inorganic materials, hybrid films have been obtained where polymers and biomolecules are combined with metallic nanoparticles and carbon nanotubes. These hybrid nanostructures normally lead to enhanced performance in sensing and biosensing. Significantly, they can also be integrated in field-effect devices, thus permitting integration of organic films and silicon technology. The course will finish with the introduction of information visualization concepts that have been recently employed in treating large amounts of data of sensors and biosensors, with unprecedented elimination of cross talk effects.

Multispectral Imagery and astronomical developments: data reconstruction, source separation, anomaly detection, and identification


Mireille Guillaume

Centrale Marseille/Institut Fresnel, Marseille, France



Multivariate analysis has been shown to be able to greatly improve the performances of imagery applications, such as detection and classification. Moreover, hyperspectral data allow material identification, by exploiting the reflectance spectrum of pure materials constituting the observed objects, even in presence of mixtures. Most of the astronomical missions include spectroscopic mode in the data acquisition process. We propose to give some basis to extract information from multi and hyper spectral data.

First we recall fundaments on random vectors and multivariate densities, and on multivariate data analysis: singular value decomposition, principal component analysis and independent component analysis.

 A second chapter is devoted to image formation, dimensionality and metrics in the multidimensional space. We present the problem of parameters estimation in large dimensional spaces. We also give the different metrics for spectrum identification and compare their respective advantages and performances.

 Then we consider two main applications: object detection and spectral unmixing.
Supervised detection is treated for multispectral and hyperspectral data, with a specific approach of each case, while unsupervised detection, which is known as anomaly detection, is in the context of hyperspectral data.

 Spectral unmixing is clearly for hyperspectral data. We present some of existing very recent methods, which can be classified in bayesian  and  algebric methods.
The expected results are given, with constraints and limitations.

The lessons are illustrated with results on hyperspectral data.


Adaptive optics for astronomy and other applications: from the optical aberrations to their correction.


Brice Le Roux,

Observatoire Astronomique de Marseille-Provence, LAM, France



We begin by presenting the full process of image formation, from the atmospheric distortion of the wave front to the telescope focus image formation. We expose in that chapter the atmosphere physics and the optical consequences on the light propagation. We present the spatial and temporal statistics of the wave front and the consequences on the image quality.

We propose a historical panorama of the solutions that were found to that problem from speckle analysis to adaptive optics.

The second chapter presents the components of adaptive optics systems and their limitations. Different type of wave front sensors, deformable mirrors and real time computers are described and compared. In that chapter, we also present the control loop optimisation strategies in classical adaptive optics. From the intuitive integrator to the optimal Linear Quadratic Gaussian control. Finally, this chapter ends with the description of an error budget for adaptive optics and presentation of the main limitations of such a system.

A third chapter is dedicated to the presentation of next generation adaptive optics systems. We explain the astronomical objectives in terms of angular resolution or field of view that make it necessary to improve the adaptive optics performances. We describe the wide field of view adaptive optics concepts (GLAO, LTAO, MCAO and MOAO) and the extreme adaptive optics systems. In each case, we detail the constraints and specificities in terms of technology and control algorithm. We present each time an example of a real project implying such a system. We end the chapter by a section dedicated to the characteristics and specific constraints of adaptive optics for an Extremely Large Telescope, in terms of technology and control law.

Finally, the applications of adaptive optics in other academic or industrial fields are presented. We detail each time the specific constraints of particular applications and the technical solutions.